In a structure, such as a house, various sensors may be mounted to the walls and ceilings. For example, carbon monoxide detectors and smoke detectors are two common types of sensors that are ubiquitous in households, offices, and other locations. While such sensors serve important safety functions, occupants of the structure also want to be surrounded by visually pleasing devices. These devices include many components that require exposure to the air, such as the carbon monoxide sensors. Additionally, the detectors include buzzers or other sound-generating components that are required to produce sufficiently loud sounds to be heard by people within the structure. As a result, the outer casing or grille of the detectors includes one or more apertures through which air and sound waves may pass. While functionally necessary, these apertures allow some or all of the interior components of the detector to be visible.